[alsa-devel] Multiple codecs on one sound card for multi-channel sound card

[Caleb Crome]

(re-sending hope it's not a duplicate -- I think I must have had HTML
in my previous email and it was ignored)

 Hi all,
    What are the current best practices to specify multiple codecs on
one sound card, with all codecs sharing a single TDM bus?

 I have a card with up to 32 TLV320AIC33 codecs on it.  For the
moment, we can limit the discussion to only 16 codecs, so we don't
have to get extra serializers involved...

 I currently have something like this in my am335x-boneblack.dts file:

 (i.e. attempting to set tdm slot width and num in the i2c codec)

 but it doesn't seem to be picking up the fact that I want all the
codecs linked together as one.

 (FYI, the first codec, i.e. tlv32aic3x_a should be the master, and
all others including the CPU will be slaves).

 Thanks for any help!

 BTW, I'm happy to use whatever kernel will support me with the
minimal amount of effort, currently using 4.1



Thank you!
   -Caleb

&i2c1 {
 ...
tlv320aic3x_a: tlv320aic3x at 18 {
#sound-dai-cells = <1>;
compatible = "ti,tlv320aic3x";
reg = <0x18>;
tdm-offset = <0>;
status = "okay";
};
tlv320aic3x_b: tlv320aic3x at 19 {
#sound-dai-cells = <1>;
compatible = "ti,tlv320aic3x";
reg = <0x19>;
tdm-offset = <32>;
status = "okay";
};
tlv320aic3x_c: tlv320aic3x at 1a {
#sound-dai-cells = <1>;
compatible = "ti,tlv320aic3x";
reg = <0x1a>;
tdm-offset = <64>;
status = "okay";
};
tlv320aic3x_d: tlv320aic3x at 1b {
#sound-dai-cells = <1>;
compatible = "ti,tlv320aic3x";
reg = <0x1b>;
tdm-offset = <96>;
status = "okay";
};
};

&mcasp0 {
#sound-dai-cells = <0>;
pinctrl-names = "default";
pinctrl-0 = <&mcasp_0_pins_default>;
status = "okay";

op-mode = <0>;          /* MCASP_IIS_MODE */
tdm-slots = <16>;
num-serializer = <16>;
serial-dir = <  /* 0: INACTIVE, 1: TX, 2: RX */
0 0 1 2
0 0 0 0
0 0 0 0
0 0 0 0
>;
tx-num-evt = <1>;
rx-num-evt = <1>;
};

/ {
sound {
compatible = "simple-audio-card";
simple-audio-card,name = "puppy-audio";
simple-audio-card,mclk-fs = <256>;
system-clock-frequency = <12288000>;
status = "okay";
simple-audio-card,bitclock-master = <&tlv320aic3x_a>;
      simple-audio-card,frame-master    = <&tlv320aic3x_a>;
simple-audio-card,widgets =
"Line", "Line Out",
"Line", "Line In";
simple-audio-card,routing =
"Line Out",       "HPLOUT",
"Line Out",       "HPROUT",
"Line In",        "LINE1L",
"Line In",        "LINE1R";

simple-audio-card,dai-link at 0 {
format = "left_j";
cpu {
sound-dai = <&mcasp0>;
};
codec {
sound-dai = <&tlv320aic3x_a 0>;
dai-tdm-slot-num = <0>;
dai-tdm-slot-width = <16>;
};
};
/**** The stuff below doesn't work -- I can't figure out how to get
the name_prefixes set
 on each codec... .How do I set up so that each codec gets its own name prfix
and so that the soc core thinks all codecs are on the same DAI?
**** */

// simple-audio-card,dai-link at 1 {
// format = "left_j";
// cpu {
// sound-dai = <&mcasp0>;
// };
// codec {
// sound-dai = <&tlv320aic3x_b 0>;
// dai-tdm-slot-num = <2>;
// dai-tdm-slot-width = <16>;
// };
// };
// simple-audio-card,dai-link at 2 {
// format = "left_j";
// cpu {
// sound-dai = <&mcasp0>;
// };
// codec {
// sound-dai = <&tlv320aic3x_c>;
// dai-tdm-slot-num = <4>;
// dai-tdm-slot-width = <16>;
// };
// };
// simple-audio-card,dai-link at 3 {
// format = "left_j";
// cpu {
// sound-dai = <&mcasp0>;
// };
// codec {
// sound-dai = <&tlv320aic3x_d>;
// dai-tdm-slot-num = <6>;
// dai-tdm-slot-width = <16>;
// };
// };
};
};